My girlfriend and I did a hike to Everest Base Camp in December 2010. I can recommend this period of time for trekking, because there aren’t too many other hikers so accommodation is cheap and it’s not a touristic adventure. Plus in the daytime it’s always nice and sunny, so it’s only cold in the evening. We did the hike on our own (so no porter or guide). But this wasn’t possible if we didn’t meet Kedar Neupane. This incredibly friendly man spoke Engelish very well and did everything he could to help us. He helped us arranging the flying tickets and took us to a rentalshop for the extraneeded materials. Kedar knows his own country and will help you to find the adventure you need!!
This was by far the most extraordinary and beautifull trip is made in Asia, and I can recommend this company if you go to Nepal.